Recovery of Zinc and Sulfur from Sphalerite Concentrates by Reaction with Sulfuric Acid

摘要

The Bureau of Mines constructed a process research unit (PRU) to demonstrate new technology for extracting zinc from sphalerite concentrates. Up to 9 kg/hr of sphalerite (ZnS) concentrate was reacted at ambient pressure in the PRU with 80 pct sulfuric acid at 160 to 180C to produce zinc sulfate and elemental sulfur. The PRU consisted of a three-stage glass reactor system: a 4-liter premix stage in which feed was slurried with 78 to 82 pct H2SO4, a 40-liter stirred reactor, and a 150-liter settling stage in which high reaction conversions were effected and excess H2SO4 for recycle was separated from insoluble ZnSO4 and sulfur. Evolution of sulfur-containing gases was minimized by subsurface addition of acid feed slurry to the stirred reactor and by exclusion of air from the reactor to prevent the oxidation of elemental sulfur.